1. Technical Field
The present invention relates to a stirling cycle system driving device, and more particularly to a stirling cycle system driving device having circumference cams instead of a crank shaft so that the device can be compact and the quantity of working fluid can be decreased, in which device a phase angle between a displacer rod and a piston rod can be regulated so that the output power of the device can be regulated even after fabrication of the device, and in which device a vibration due to the gap of a cam guiding groove is restrained and one side wearing of surfaces of a cam guiding groove is prevented.
2. Prior art
FIG. 1 shows a conventional stirling cycle system driving device having a crank shaft c. If a tool phase angle .alpha. is set in the crank shaft C and the crank shaft C is rotated, a displacer D and a piston P connected to the respective ends of crank arms move upward and downward linearly, and a track of volume changing to have a desired volume phase angle .beta. is produced by the reciprocal action of the displacer D and the piston P, thereby the system is driven. In this case, said tool phase angle .alpha. means the angle between the crank arms respectively connected to the displacer D and the piston P, and said volume phase angle .beta. means the difference between a rotation angle of the crank shaft to the top point I of the stroke of the displacer and that to the top point II of the stroke of the piston. In FIG. 1, the axis X indicates a rotation angle of the crank shaft, and the axis Y indicates strokes of the displacer and the piston.
A conventional stirling cycle system driving device as described above has several defects as follows:
1. A crank shaft is included in the device, and a space larger than the rotating radius of the crank arms is needed for a crank chamber within which the crank shaft and the crank arms rotate, thereby it is difficult for the device to be compact.
2. Due to the same reason as in the defect 1, the quantity of working fluid must be increased, thereby the manufacturing cost is increased.
3. A separate procedure for manufacturing a crank chamber must be added.
4. The tool phase angle .alpha. of the crank shaft must be changed to revise the volume phase angle .beta. for performance compensation of the device, and the crank shaft must be remanufactured to change the tool phase angle .alpha., thereby the development and the modification of the device are considerably difficult.
Meanwhile, U.S. patent Ser. No. 3,940,932 granted to Ambrose et al. discloses a stirling cycle system using cam grooves. Said Patented system has a construction that a power piston and a recovery piston are spaced apart from each other and the respective piston rollers can be contact with cam grooves formed in a fly wheel, thereby the temperature difference between the hot and the cold sides of the system is increased so that power loss is decreased and efficiency is improved. However, there are shortcomings that said system requires much more space than a convectional stirling cycle system using a crank shaft due to the separated construction of the power piston and the recovery piston, and that a steady output of power is not produced because piston rollers and cam grooves are not steadily in contact with each other.